The present invention is generally related to audio signal processing devices. More particularly certain embodiments of the present invention relate to user interfaces for equipment used in the production and monitoring of surround audio programs.
In the early 1970's quadraphonic audio was introduced as the first commercialized surround audio reproduction system, but faded from the scene due to various technical difficulties and a lack of industry standardization on quadraphonic encoding formats. In more recent years however, surround audio production has made a comeback with the advent of digital audio codecs (e.g. AC-3, DTS) which allow a large number of audio channels to be stored or transmitted with high coding efficiency and with sufficiently good reproduction quality for theatre and home entertainment delivery. As a result of these technological advances and the ensuing demand for surround audio program material, there has been an increase in the diversity and availability of audio equipment specifically adapted for surround audio production applications.
In a surround audio recording or mixdown session, the layout and user interface of the associated production equipment makes a significant difference in the efficiency of the production process. A poorly thought-out design can seriously impede the smoothness and speed of normal audio production work, while a well-designed and intelligent user interface can help to make the work progress quickly and effortlessly. User interface design is a subtle art, and time-tested classic approaches do not always translate well to modern applications. Persons involved in the production of surround audio programs are constantly seeking to optimize productivity, and therefore there is an existing need to improve the user interface of surround audio production equipment.
Creating surround audio mixes has long been a standard practice for feature film productions and recently surround audio mixing has become more common in television and music production environments as well. In order to help engineers better ensure the quality and consistency of the resulting surround audio mixes, a special class of audio signal processing devices has emerged known as surround monitor controllers.
Among other functions, surround monitor controllers provide a means for the selection, combination and control of channels which carry surround audio from the outputs of the mixer to the control room monitor loudspeakers. Functions typically associated with each monitor channel include “solo” which selects a channel or group of channels exclusively for audible reproduction, and “mute” which excludes the muted channel from audible reproduction while leaving the other channels undisturbed. These functions have been inherited from the art of audio mixers (or “consoles”) dating back to the earliest days of audio production.
The EMT-Franz's A-400 broadcast mixer had solo and mute functions combined on a simple mechanically latching toggle switch to be switched forward for solo and switched backward for mute. More typically solo and mute functions have been located separately on mechanically latching push-buttons, for example on vintage NEVE® and API® mixing consoles. Muting usually happens post-fader in the channel signal path, while solo may often be switchable between pre-fader and post-fader operation.
Some manufacturers of surround monitor controllers have sought to reduce the physical footprint and cost of their products by optimizing user interface features for the needs of surround monitoring applications. TASCAM® manufactures the DS-M7.1 Professional Digital Surround Monitor Controller, which features a single logic button for each monitor channel along with a “solo/mute” selector button, which modifies the function of all the channel buttons between solo and mute. Other surround monitor controllers, such as the Grace Design's m906 5.1 Monitor Controller and the RTW's SurroundControl series monitor controllers, employ a similar bimodal switching scheme. This approach requires the user to have constant knowledge of the “solo/mute” mode in order to use the channel buttons correctly. It is more desirable in the design of an effective user interface to avoid such bimodal switching schemes.
CRANE SONG LTD.® manufactures the Avocet Discrete Class A Studio Controller. The Avocet Discrete Class A Studio Controller also features a single button for each monitor channel. In normal operation the channel buttons are simple electronically latched “on-off” buttons which effectively perform the function of a conventional mute switch, but by holding a channel button for at least half a second the corresponding channel may be soloed in an electronically latching mode. In order to un-solo the channel, the button must be held again for at least half a second, at which point the channel reverts to the state it was prior to soloing. While the Avocet Discrete Class A Studio Controller avoids having an additional mode switching button to achieve solo-mute functionality, the user is still required to remember the button state for correct use, and there is also a significant time delay to engage and disengage solo. It is more desirable to provide an interface that avoids actuation time-delay.
U.S. Pat. No. 6,061,458 (East, et al.) discloses an audio mixing console with channel solo functions operable in several modes by electronically latching momentary logic buttons. Muting functions are located on separate user controls from solo functions. It is more desirable to provide a solo-mute switching apparatus which requires less physical space. US Published application 2003/0076966 (Okabayashi) discloses a digital mixer capable of monitoring surround signals. Mute and solo functions may be accessed through a surround monitor setting screen where first a channel is selected, and then a mode selection must be made. It is more desirable to provide a solo-mute switching apparatus which does not require multiple user actions or menus in order to engage or disengage channel solo.
In light of the prior art of audio signal processing devices and in particular surround monitor controllers, there is an outstanding need for a solo-mute switching apparatus that presents a simple, intuitive user interface. The solo-mute switching apparatus should minimize cost and space while avoiding bimodal buttons, actuation delay, menus and other undesirable user interface characteristics.